A roller crusher generally has two crush rollers. Roller crushers are used particularly for the comminution, particularly high-pressure comminution, of coarse mineral material, such as ores, cement clinker, slag, kimberlite, coal or ceramic base materials. Roller crushers of this type are also referred to as high compression roller mills. However, the invention also comprises roller crushers for compacting or briquetting material.
In the processing and particularly the comminution of brittle, granular material using such a roller crusher, high forces are applied and the surfaces of the rolls are under great stress, so that protecting the roller surfaces against wear is generally of special importance. Thus it is known in practice to protect roller surfaces against wear by using cylindrical hard metal pins and/or studs that are embedded “hedgehog-like” in corresponding blind bores in the roller body, and together with the material to be crushed between the rolls, form an autogenous layer of wear protection (see EP 0 516 952 [U.S. Pat. No. 5,269,477]). However, this type of wear protection is generally unsatisfactory in the region of the roller ends due to the high risk of the pins breaking off at the edges. For this reason, measures specifically for protecting the edges and/or for wear protection at the edges of the roller have been proposed.
For instance, a generic crush roller is known from EP 0 516 952, in which cylindrical hard metal pins are incorporated into the roller body for wear protection, and pockets that are designed as open axially and radially outward are also provided along the roller ends, with plate-shaped, wear-resistant inserts in the pockets. The spacing between these edge protectors along the angular direction of the roller corresponds approximately to the spacing between the nub pins embedded in the remaining regions of the roll. However, the wear protection thereby achieved at the edges is unsatisfactory.
For this reason, alternative edge protection concepts have been proposed, in which replaceable edge protectors are fitted into angularly extending annular grooves that are open axially and radially outward.
For instance, EP 1 502 650 [EP 7,510,135] describes a crush roller having angularly extending pockets in the form of annular shoulders arranged along the end edges of the roll, wherein in each of these pockets, a plurality of wear protection elements are set one next to the other angularly. The wear protection elements that are made of hard metal and form a quasi-closed ring that is designed to provide high wear protection. The wear protection elements can be mounted directly in the annular shoulders by gluing, clamping or soldering. In general, the wear protection elements are fastened angularly close to one another and therefore, no autogenous wear protection between the elements is formed.
The same is true of a crush and/or grinding roller known from EP 1 684 907 [U.S. Pat. No. 7,497,396] for the high-pressure comminution of granular material, in which a plurality of hard bodies are arranged on the end face edges in an annular groove of the roller outer surface for the purpose of edge protection, with such hard bodies projecting both axially from the end face and radially from the surface of the roller outer surface.
An alternative wear protection concept is described in EP 0 659 108 [U.S. Pat. No. 5,755,033]. The wear layer of the crush roller essentially has planar zones made of a highly wear-resistant material that can be formed, for example from ceramic tiles and/or glazed tiles. The interstices between the highly wear-resistant zones are filled with a material of different wear resistance. The ceramic tiles and/or glazed tiles can be produced, for example from a metal matrix composite material by hot isostatic pressing. These prefabricated hard bodies are then permanently mounted, together with the interstice material, onto the base body by hot isostatic pressing.